/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * $Id: escape.c,v 1.44 2008-10-08 01:17:51 danf Exp $
 ***************************************************************************/

/* Escape and unescape URL encoding in strings. The functions return a new
 * allocated string or NULL if an error occurred.  */

#include "setup.h"
#include <api/libcurl/curl.h>

#include "memory.h"
/* urldata.h and easyif.h are included for Curl_convert_... prototypes */
#include "urldata.h"
#include "easyif.h"

#define _MPRINTF_REPLACE /* use our functions only */
#include <api/libcurl/mprintf.h>

/* The last #include file should be: */
#include "memdebug.h"

/* Portable character check (remember EBCDIC). Do not use isalnum() because
its behavior is altered by the current locale. */
static bool Curl_isalnum(unsigned char in)
{
	switch (in)
	{
	case '0': case '1': case '2': case '3': case '4':
	case '5': case '6': case '7': case '8': case '9':
	case 'a': case 'b': case 'c': case 'd': case 'e':
	case 'f': case 'g': case 'h': case 'i': case 'j':
	case 'k': case 'l': case 'm': case 'n': case 'o':
	case 'p': case 'q': case 'r': case 's': case 't':
	case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
	case 'A': case 'B': case 'C': case 'D': case 'E':
	case 'F': case 'G': case 'H': case 'I': case 'J':
	case 'K': case 'L': case 'M': case 'N': case 'O':
	case 'P': case 'Q': case 'R': case 'S': case 'T':
	case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':
		return TRUE;
	default:
		break;
	}
	return FALSE;
}

/* for ABI-compatibility with previous versions */
char *curl_escape(const char *string, int inlength)
{
	return curl_easy_escape(NULL, string, inlength);
}

/* for ABI-compatibility with previous versions */
char *curl_unescape(const char *string, int length)
{
	return curl_easy_unescape(NULL, string, length, NULL);
}

char *curl_easy_escape(CURL *handle, const char *string, int inlength)
{
	size_t alloc = (inlength ? (size_t)inlength : strlen(string)) + 1;
	char *ns;
	char *testing_ptr = NULL;
	unsigned char in; /* we need to treat the characters unsigned */
	size_t newlen = alloc;
	int strindex = 0;
	size_t length;

#ifndef CURL_DOES_CONVERSIONS
	/* avoid compiler warnings */
	(void)handle;
#endif
	ns = malloc(alloc);
	if (!ns)
		return NULL;

	length = alloc - 1;
	while (length--)
	{
		in = *string;

		if (Curl_isalnum(in))
		{
			/* just copy this */
			ns[strindex++] = in;
		}
		else
		{
			/* encode it */
			newlen += 2; /* the size grows with two, since this'll become a %XX */
			if (newlen > alloc)
			{
				alloc *= 2;
				testing_ptr = realloc(ns, alloc);
				if (!testing_ptr)
				{
					free( ns );
					return NULL;
				}
				else
				{
					ns = testing_ptr;
				}
			}

#ifdef CURL_DOES_CONVERSIONS
			/* escape sequences are always in ASCII so convert them on non-ASCII hosts */
			if (!handle ||
					(Curl_convert_to_network(handle, &in, 1) != CURLE_OK))
			{
				/* Curl_convert_to_network calls failf if unsuccessful */
				free(ns);
				return NULL;
			}
#endif /* CURL_DOES_CONVERSIONS */

			snprintf(&ns[strindex], 4, "%%%02X", in);

			strindex += 3;
		}
		string++;
	}
	ns[strindex] = 0; /* terminate it */
	return ns;
}

/*
 * Unescapes the given URL escaped string of given length. Returns a
 * pointer to a malloced string with length given in *olen.
 * If length == 0, the length is assumed to be strlen(string).
 * If olen == NULL, no output length is stored.
 */
char *curl_easy_unescape(CURL *handle, const char *string, int length,
						 int *olen)
{
	int alloc = (length ? length : (int)strlen(string)) + 1;
	char *ns = malloc(alloc);
	unsigned char in;
	int strindex = 0;
	long hex;

#ifndef CURL_DOES_CONVERSIONS
	/* avoid compiler warnings */
	(void)handle;
#endif
	if ( !ns )
		return NULL;

	while (--alloc > 0)
	{
		in = *string;
		if (('%' == in) && ISXDIGIT(string[1]) && ISXDIGIT(string[2]))
		{
			/* this is two hexadecimal digits following a '%' */
			char hexstr[3];
			char *ptr;
			hexstr[0] = string[1];
			hexstr[1] = string[2];
			hexstr[2] = 0;

			hex = strtol(hexstr, &ptr, 16);

			in = (unsigned char)hex; /* this long is never bigger than 255 anyway */

#ifdef CURL_DOES_CONVERSIONS
			/* escape sequences are always in ASCII so convert them on non-ASCII hosts */
			if (!handle ||
					(Curl_convert_from_network(handle, &in, 1) != CURLE_OK))
			{
				/* Curl_convert_from_network calls failf if unsuccessful */
				free(ns);
				return NULL;
			}
#endif /* CURL_DOES_CONVERSIONS */

			string += 2;
			alloc -= 2;
		}

		ns[strindex++] = in;
		string++;
	}
	ns[strindex] = 0; /* terminate it */

	if (olen)
		/* store output size */
		*olen = strindex;
	return ns;
}

/* For operating systems/environments that use different malloc/free
   systems for the app and for this library, we provide a free that uses
   the library's memory system */
void curl_free(void *p)
{
	if (p)
		free(p);
}
